Since McCutchen made his major league debut in June 2009, Pittsburgh has had 18 losing streaks of at least five games. The Pirates dropped 12 in a row during their 105-loss 2010 season.

"We've been there before, we know how it feels, so we knew if we were able to get on the board early, we pretty much would have them," McCutchen said. "Just because we've been there. When you're (struggling), and then you're down early, it kind of knocks the breath out of you."

Alvarez hit a three-run homer in the first, giving Pittsburgh a lead it would never relinquish. A six-run sixth gave the Pirates a 10-0 lead before the Cubs scored all of their runs in the final two innings.

"Not only to not get results, but to feel like you are getting embarrassed, it is frustrating," Cubs catcher Koyie Hill said.

This is the Cubs' worst slide since they started out 0-14 in 1997. Few of their losses during this streak were wipeouts -- six were by one run, including the first two games of this series.

Starlin Castro homered during a three-run eighth for Chicago, which had scored only two runs in its previous 33 innings.

Alvarez's homer was Pittsburgh's first this season with more than one man on. McCutchen added a solo shot in the fifth and Jones went deep to right with Neil Walker on in the fifth.

Pittsburgh completed its first three-game sweep at PNC Park since Sept. 17-19, 2010.

The lowest-scoring team in baseball, the Pirates set a season high for runs and matched a season high by winning their third consecutive game.

Alvarez homered for the first time in 24 days in the first inning, taking a 3-1 pitch from Matt Garza (2-3) deep up into the elevated seats in right-center.

"I was well aware of the fact we didn't have (a three-run homer)," Pittsburgh manager Clint Hurdle said. "They make the offensive game pick up dramatically when you can get three runs in one swipe. About time for us to get one of those."

McCutchen retied Alvarez for the team lead with his eighth home run, in the fifth inning.

Jones snapped an 0-for-11 stretch when he pulled Garza's final pitch deep into the right-field seats.

That was only the beginning for the Pirates in their six-run sixth. Demoted from the closer's role after losing Saturday night's game when he hit Matt Hague with a pitch with the bases loaded, Rafael Dolis came in and walked both batters he faced.

After Bedard sacrificed, pinch-hitter Gorkys Hernandez lined a single to center off Michael Bowden for his first hit and first two RBIs in the majors.

Alvarez added a sacrifice fly and Walker an RBI single to give the Pirates 10 runs in a game for the first time since July 3, 2011.

Bedard (3-5) allowed two hits. He had four walks and three strikeouts.

"To get on a roll like that and score 10 runs, it's nice," said Bedard, who has four losses this season when he allowed two earned runs or less. "It makes it easier for a pitcher to pitch."

After allowing five runs over a stretch of four starts, Garza has been tagged for a total of 13 over eight innings in his past two outings. He gave up five earned runs on seven hits, a walk and six strikeouts Sunday.

"It's frustrating. The last couple have been frustrating," Garza said. "I need to keep going and going hard. It's going to turn -- and it's got to turn.

"There are no excuses," he added. "We are going to turn it around, and we are going to keep plugging away until it turns."

Game notes

The Cubs completed an 0-6 road trip during which they were not outhit in a game until Sunday. ... Pirates OF Jose Tabata was 2 for 3 before being removed from the game in the sixth inning due to discomfort and cramping in his left leg. He was to be further evaluated later Sunday and Monday. ... Sveum said that either RHP Shawn Camp or LHP Jeff Russell would work in closing situations. Dolis has been scored on in each of his past five outings. ... Chicago returns home for a three-game series against San Diego in a matchup of the NL's two worst teams. ... Pittsburgh continues a nine-game in which it is 4-2 when it faces NL Central-leading Cincinnati on Monday.